M. Wu: ENEE631 Digital Image Processing (Fall'01) Medical Imaging Topic: Medical Imaging Topic: Radon Transform & Inverse Radon Transf. Radon Transform & Inverse Radon Transf. Min Wu Electrical & Computer Engineering Univ. of Maryland, College Park http://www.ece.umd.edu/class/enee631/ [email protected]ENEE631 Fall ENEE631 Fall 2001 2001 Lecture-22 Lecture-22
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M. Wu: ENEE631 Digital Image Processing (Fall'01) Medical Imaging Topic: Radon Transform & Inverse Radon Transf. Min Wu Electrical & Computer Engineering.
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ENEE631 Fall ENEE631 Fall 20012001Lecture-22Lecture-22
M. Wu: ENEE631 Digital Image Processing (Fall'01)Lec22 – Medical Imaging / 2nd Course
Review 11/27/01 [2]
Last TimeLast Time
Sampling rate conversion– Generalization: lattice, Voronoi cells, and reciprocal lattice
– Ideal approach for sampling lattice conversion
– Simplified conversion approaches
Binary image processing– Detect line patterns
– Filling holes via morphological operations
This time– Medical imaging topic
– Review of course material
M. Wu: ENEE631 Digital Image Processing (Fall'01)Lec22 – Medical Imaging / 2nd Course
Review 11/27/01 [3]
Non-Intrusive Medical DiagnosisNon-Intrusive Medical Diagnosis
(From Jain’s Fig.10.1)
M. Wu: ENEE631 Digital Image Processing (Fall'01)Lec22 – Medical Imaging / 2nd Course
Review 11/27/01 [4]
Non-Intrusive Medical Diagnosis (cont’d)Non-Intrusive Medical Diagnosis (cont’d) Observe a set of projections (integrations) along different
angles of a cross-section– Each projection itself loses the resolution of inner structure
– Types of measurements transmission (X-ray), emission, magnetic resonance (MRI)
Want to recover inner structure from the projections– “Computerized Tomography” (CT)
(From Bovik’s Handbook Fig.10.2.1)
Emission tomography: measure emitted gamma rays by the decay of isotopes from radioactive nuclei of certain chemical compounds affixed to body parts.
MRI: based on that protons possess a magnetic moment and spin. In magnetic field => align to parallel or antiparallel. Apply RF => align to antiparallel. Remove RF => absorbed energy is remitted and detected by Rfdetector.
M. Wu: ENEE631 Digital Image Processing (Fall'01)Lec22 – Medical Imaging / 2nd Course
Review 11/27/01 [5]
Radon TransformRadon Transform
A linear transform f(x,y) g(s,)– Line integral or “ray-sum”
– Along a line inclined at angle from y-axis and s away from origin
Fix to get a 1-D signal g(s)
dxdysyxyxfsg )sincos(),(),(
rotation) e(coordinat cossin
sincos where
)cossin,sincos(
y
x
u
s
duususf
(From Jain’s Fig.10.2)
M. Wu: ENEE631 Digital Image Processing (Fall'01)Lec22 – Medical Imaging / 2nd Course
Review 11/27/01 [6]
Example of Image Radon TransformExample of Image Radon Transform